Radar-Based Particle Localization in Densely Packed Granular Assemblies

Abstract

Particle tracking in densely packed granular assemblies is of great interest in mechanical process engineering. In this contribution, a radar-based system for particle localization as an initial step towards tracking is presented. This system comprises six transmitting and receiving antennas forming a “multiple-input multiple-output” setup positioned around a cuboidal reactor. The reactor is a standard batch grate system, which contains stationary spherical polyoxymethylene particles with a 10 mm diameter and a spherical steel tracer particle with a 20 mm diameter. The tracer is positioned at various locations at an optically transparent reactor wall. Electromagnetic waves must pass through the remaining three reactor walls to detect the tracer particle. Operating in the Frequency Modulated Continuous Wave mode within a 1.5 to 8.5 GHz frequency range, we compared radar-detected tracer positions with those from camera images. The results demonstrate a vertical localization accuracy with a standard deviation of σvert= 0.86 cm and a horizontal position accuracy with σhor= 0.17 cm. This study not only presents the achievements of radar-based particle localization but also delves into the potential and challenges of applying this technology to a specific measurement scenario within mechanical process engineering.

Enhanced Tracer Particle Detection in Dynamic Bulk Systems Based on Polarimetric Radar Signature Correlation

“…This assumption is deemed appropriate for the conducted measurements, given the robustness of the setup. Consequently, the calculated apparent permittivity is ε r,bulk = 2.03, aligning well with the reported value in [20].…”

“…Additionally, the most pronounced clutter appears in the direction of propagation (φ = 0 • ) and in the backscatter case (φ = 180 • ) for the co-polarization. This is why, in [20], only channels of bistatic angle were utilized. Regarding cross-polarization, the clutter is evenly distributed over the azimuth orbit.…”

“…The sphere under consideration does not exhibit any distinctive frequency-dependent behavior or heightened scattering characteristics that facilitate its detection. Nevertheless, the sphere can be effectively detected in randomized beds through radar measurements, as demonstrated in [20]. This capability stems from the radar approach, which permits spatial or temporal resolution of the measurement.…”

“…Lately, a MIMO frequency-modulated continuous-wave (FMCW) radar approach alongside a metallic sphere particle as a tracer has been used [20]. In Figure 1, the principle measurement setup is illustrated.…”